Memory systems in electronic systems are typically used to store data for retrieval at a later time. Memory systems come in different types of memory. For example, one type of memory is a “volatile” memory, which can store data only when supplied with power. Volatile memory systems are typically designed as dynamic random access memory (DRAM) or static random access memory (SRAM) systems, each having different memory cell configurations. These types of memory systems are often used in computer systems and other processor-based systems for storing data used during processing. Another type of memory system is a “non-volatile” memory system, which can store data even when power is not supplied. There are different designs for non-volatile memory, including NAND-type flash memory and NOR-type flash memory, each having a different memory cell arrangement and manner of accessing data stored by the memory cells. Non-volatile memory systems are used in applications where data should be continuously stored, even when the electronic system including the non-volatile memory is switched off. Cellular phones, digital cameras, personal digital assistants, digital music players, are some examples of where non-volatile memory systems are used.
Memory systems can also be implemented in different forms. For example, a memory system can be implemented as an individual memory device. Individual memory devices can be electrically coupled and mounted together on a common substrate to form a memory module, which is then coupled to an electronic system, such as a computer system. Individual memory devices can also be electrically coupled and mounted to a substrate on which other components of an electronic system are also mounted. Memory systems can also be “embedded” in an electronic system. That is, the memory system is formed on a common semiconductor with other electrical circuitry of an electrical system. As illustrated by the previous discussion, memory systems come in different types and arrangements, and are used in a wide range of electronic systems.
In many portable electronics applications which utilize batteries for supplying power, having a memory system designed for low power consumption is desirable. There are many different approaches to reducing power consumption of memory systems, many of which focus on reducing power consumption of memory systems during access operations, such as reading data from or writing data to a memory array. However, reduced power consumption can often compromise the speed of the memory system. As known, operation of memory systems involve driving electrical signals over internal signal lines. The electrical signals can represent internal control signals, data signals, clock signals, as well as other signals. Proper operation of a memory system require that these electrical signals are driven to required signal levels. In a memory system designed for lower power consumption, less power is typically available to drive electrical signals to required voltage or current levels, forcing the memory system to operate at slower speeds. Although slower operating memory systems may be acceptable in some applications, it is desirable to reduce power consumption without negatively impacting the performance of the memory system.
Therefore, there is a need for alternative approaches to reducing power consumption of memory systems without compromising memory system performance.